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Numerical investigation to evaluate the effects of gravity and pressure on flame structure and soot formation of turbulent non-premixed methaneair flame

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Propulsion and Power Research 2022年第4期11卷 473-495页

作者： Subrat Garnayak Amjad Ali Pasha Radi Alsulami Medhat A.Nemitallah Abdul Gani Abdul Jameel sukanta k.dash V.Mahendra Reddy School of Energy Science&Engineering Indian Institute of Technology KharagpurWest Bengal721302India Department of Aerospace Engineering King Abdulaziz UniversityJeddah21589Saudi Arabia Department of Mechanical Engineering King Abdulaziz UniversityJeddah21589Saudi Arabia IRC-Hydrogen and Energy Storage and Mechanical Engineering Department King Fahd University of Petroleum and MineralsDhahran31261Saudi Arabia Department of Chemical Engineering King Fahd University of Petroleum and MineralsDhahran31261Saudi Arabia Center for Refining&Advanced Chemicals King Fahd University of Petroleum and MineralsDhahran31261Saudi Arabia Department of Mechanical Engineering Indian Institute of Technology KharagpurWest Bengal721302India

In this study,a turbulent non-premixed(diffusion)methane-air flame has been investigated computationally to analyze the influences of pressure and gravity on flame structure and sooting characteristics between 1 and 10 *** simulation has been conducted in a 2-D axisymmetric computational domain using the finite volume-based computational fluid dynamics(CFD)*** interaction of turbulence and chemistry is modeled by considering the steady laminar flamelet model(SLFM)and the GRI Mech 3.0 chemical *** radiative heat transfer calculation is carried out by considering the discrete ordinate(DO)method and the weighted sum grey gas model(WSGGM).The semi-empirical Moss-Brookes model is considered to calculate *** impact of gravity on flame and sooting characteristics are evaluated by comparing the normal-gravity flames with the zero-gravity *** effect of soot and radiation on flame temperature is also *** results show a close agreement with the measurement when both soot and radiation are included in the numerical *** rates of soot formation,surface growth,and oxidation increase with increased operating pressure,regardless of ***-gravity flames have a higher soot volume fraction,a wider soot-containing zone,a higher CO mass fraction,and a lower flame temperature than normal-gravity flames while maintaining constant *** normal-gravity flames,the CO mass fraction decreases with pressure,whereas it increases with pressure rise in flames of zero *** of zero gravity appear taller and broader compared to the flames of normalgravity for a fixed *** increase in pressure significantly reduces the flame length and width in normal-gravity ***,the pressure elevation has little effect on the shape of a zero-gravity *** outcomes of the present study will assist in fully understanding the combustion and sooting characteristics of turbulent diffusion flames that will help design and develop h

关键词： Computational fluid dynamics(CFD) Flamelet Gravity Pressure Soot

Microencapsulation of betacyanin from dragon fruit peel by complex coacervation:Physicochemical characteristics,thermal stability,and release profile of microcapsules

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Food Bioscience 2022年第5期49卷 1072-1083页

作者： G.V.S.Bhagya Raj kshirod k.dash Department of Food Engineering and Technology Tezpur UniversityTezpurAssam784028India Department of Food Processing Technology Ghani Khan Choudhury Institute of Engineering and Technology(GKCIET)MaldaWest Bengal732141India

Dragon fruit peel contains phytochemicals and natural pigment *** crude extract was extracted from the freeze-dried dragon fruit(Hylocereus undatus)peel powder using ultrasonication and betacyanin was isolated by aqueous two-phase *** pigment betacyanin extracted from the dragon fruit peels,was encapsulated using the complex coacervation *** encapsulation,four distinct carrier agents,namely maltodextrin,gum arabic,xanthan gum,and gelatin were mixed with sodium alginate to form the wall *** betacyanin microcapsule using gum arabic as the wall material had the highest encapsulation efficiency(92.265%),followed by maltodextrin(88.365%),xanthan gum(84.655%),and gelatin(80.526%).The hygroscopicity,swelling index,and solubility of the formulated four betacyanin microcapsules were in the range of 7.581-9.462 g/100 g,120.155-153.545%,and 54.645-65.216%,*** thermal stability of four microcapsules treated at 80◦C and pH 7 was revealed to have a half-life period of 55-110 *** release behaviour of microcapsules in terms of betacyanin content in simulated gastric juice were fitted with Higuchi,korsmeyer-Peppas,Weibull,and Peppas-Sahalin *** findings support the concept that microencapsulation enables the formulation of a stable product containing functional components.

关键词： Dragon fruit peel Extraction Encapsulation Complex coacervation Betacyanin

Life cycle greenhouse gas emissions from five contrasting rice production systems in the tropics

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Pedosphere 2023年第6期33卷 960-971页

作者： Pradeep k.dash Pratap BHATTACHARYYA Soumya R.PADHY Amaresh k.NAYAk Annie POONAM Sangita MOHANTY Crop Production Division Indian Council of Agriculture Research(ICAR)-National Rice Research Institute(NRRI)GuttackOdisha 753006India

Carbon footprint (CF) quantification of major rice production systems (RPSs) is a prerequisite for developing strategies for climate change mitigation in agriculture. Total life cycle greenhouse gas emissions (LC-GHGs) from rice production to consumption might provide precise CFs for RPSs. Therefore, we assessed three segments (pre-farm, on-farm, and post-farm) of LC-GHGs under five major contrasting RPSs, i.e., aerobic rice (AR), shallow lowland rice(SLR), system of rice intensification (SRI), deep water rice (DWR), and zero-tilled direct-seeded rice (ZTR), in India to determine the corresponding *** footprint was the lowest for ZTR, while LC-GHGs were the lowest for AR. Therefore, AR is an adequate option for short-term reduction of GHG emissions. However, ZTR might be promoted by incentives as a long-term strategy. Among segmental LC-GHGs, on-farm GHG emissions contributed less than the other two segmental GHG emissions. The post-farm (i.e., farm gate to consumption) segment contributed the largest proportion (54%–69%) of total LC-GHGs, followed by pre-farm (i.e., cradle to farm) segment (21%–27%) and on-farm operation (11%–23%). These findings suggest that post-farm components that contribute to maximum GHG emissions must be scientifically tackled with proactive policy initiatives. However, the data of this segment are limited and scattered. Therefore, real-time assessment of GHG emissions during post-farm operation and input transportation from cradle to farm requires more precise quantification. Although CF in SRI was higher, this system had the potential to achieve higher yields and better soil carbon storage. Therefore,SRI may be encouraged from the perspectives of food security and long-term sustainability by reducing GHG emissions by three to four times.

关键词： carbon-equivalent emission carbon footprint climate change mitigation global warming management practice soil carbon stock:

Properties of boron doped ZnO films prepared by reactive sputtering method: Application to amorphous silicon thin film solar cells

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Journal of Materials Science & Technology 2020年第20期52卷 136-143页

作者： sukanta Bose Sourav Mandal Asok k.Barua Sumita Mukhopadhyay Centre of Excellence for Green Energy and Sensor Systems Indian Institute of Engineering Science and TechnologyShibpurHowrah 711103West BengalIndia Centre for Energy Studies Indian Institute of Technology DelhiNew Delhi 110016India

Reactive sputtered boron-doped zinc oxide(BZO) film was deposited from argon,hydrogen and boron gas *** reactive sputtering technique provides us the flexibility of changing the boron concentration in the produced films by using the same intrinsic zinc oxide *** surface was obtained in the as-deposited *** surface morphology and the opto-electronic properties of the films can be controlled by simply varying the gas concentration *** varying the gas concentration ratio,the best obtained resistivity ~6.51×10^-4Ω-cm,mobility ~19.05 cm^2 V^-1 s^-1 and sheet resistance ~7.23Ω/□ were *** lower wavelength of light,the response of the deposited films improves with the increase of boron in the gas mixture and the overall transmission in the wavelength region 350-1100 nm of all the films are>85 %.We also fabricated amorphous silicon(a-Si) thin film solar cell on the best obtained BZO *** overall efficiency of the a-Si solar cell is 8.14 %,found on optimized BZO layer.

关键词： Magnetron reactive sputtering BZO Amorphous silicon Solar cells Zinc oxide(ZnO)

Insights into structural and spectroscopic characterization of Sm^(3+)doped orange rich red emitting CsMgPO_(4)phosphors

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Journal of Rare Earths 2022年第12期40卷 1837-1848,I0001页

作者： M.k.Pradhan S.dash Department of Physics and Astronomy National Institute of Technology RourkelaRourkela769008OdishaIndia

In the present study,Sm^(3+)activated inorganic orthophosphate CsMgPO_(4)(CSMP)phosphors were prepared by adopting a solid-state reaction *** structural phase purity and morphological features were studied by X-ray powder diffraction(XRD)and scanning electron microscopy(SEM),*** molecular structure and vibrational modes were substantiated with the Fourier transform infrared spectroscopy(FTIR)and Raman spectroscopy *** optical bandgap of the host and Sm^(3+)doped phosphors was deduced from the diffused reflectance(DR)spectra with a typical value of 5.72 eV and a small variation is observed with increasing concentrations.A systematic study of photoluminescence(PL)properties of Sm^(3+)doped CSMP phosphors was carried *** the room temperature excitation and emission spectra,it is found that the phosphor emits in the orange rich red light under the suitable excitation of 402 nm in the UV region and concentration quenching occurs at x=0.02 doping *** emission peaks observed at around 562,598 and 644 nm confirm the characteristic Sm^(3+)4 f-4 f *** temperature-dependent photoluminescence(TD-PL)of the x=0.02(optimum doping)is recorded from 30 to 210℃,showing good thermal stability even at 150℃.The thermal quenching mechanisms are discussed based on the configuration coordinate model of excitation and *** prepared phosphors are found to exhibit near thermal stability compared to the commercially available red *** decay time and quantum efficiency were *** colour coordinates are found to lie in the orangish-red region of the colour *** the prepared phosphors CSMP:x Sm^(3+)can be useful as a red component in designing UV excitable chip-based phosphor-converted white LED applications.

关键词： Charge compensation Red phosphors Thermal stability Configuration coordinate model Luminescence Rare earths

Structural, electronic, and mechanical properties of cubic TiO_2:A first-principles study

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Chinese Physics B 2018年第1期27卷 492-500页

作者： Debashish dash Chandan k Pandey Saurabh Chaudhury Susanta k Tripathy Department of Electrical Engineering National Institute of TechnologySilchar Assam Department of Electronics and Communication Engineering National Institute of TechnologySilchar Assam

We present an analysis of structural, electronic, and mechanical properties of cubic titanium dioxide （TiO2） using an all electron orthogonalzed linear combinations of atomic orbitals （OLCAO） basis set under the framework of density functional theory （DFT）. The structural property, especially the lattice constant a, and the electronic properties such as the band diagram and density of states （DOS） are studied and analyzed. The mechanical properties such as bulk moduli, shear moduli, Young＇s Moduli, and Poison＇s ratio are also investigated thoroughly. The calculations are carried out on shear moduli and anisotropy factor for cubic TiO2. The Vickers hardness is also tested for fluorite and pyrite cubic-structured TiO2. Furthermore, the results are compared with the previous theoretical and experimental results. It is found that DFT- based simulation produces results which are approximation to experimental results, whereas the calculated elastic constants are better than the previous theoretical and experimental values.

关键词： density functional theory cubic TiO2 structural electronic and mechanical properties

Tectonic Setting of the kadiri Schist Belt, Andhra Pradesh, India

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Acta Geologica Sinica(English Edition) 2017年第6期91卷 1992-2006页

作者： sukanta GOSWAMI Pradeep k.UPADHYAY Purnajit BHATTACHARJEE Malaiandi G.MURUGAN Atomic Minerals Directorate for Exploration and Research Department of Atomic Energy

Plate tectonic activity has played a critical role in the development of petrotectonic associations in the kadiri schist belt. The calc alkaline association of basalt, andesite, dacite and rhyolite （BADR） is the signature volcanic rock suite of the convergent margin. The N-S belt has gone below the unconformity plane of Cuddapah sediments. In the northern part geochemical and structural attributes of the kadiri greenstone belt is studied along with microscopic observations of selected samples. Harker diagram plots of major elements generally indicate a liquid line of descent from a common source, such that BADR rocks are derived from a common parent magma of basaltic to andesitic composition. These calc-alkaline volcanic rocks are formed at convergent margins where more silicic rocks represent more highly fractionated melt. All the litho-units of this greenstone belt indicate crush and strain effects. The stretched pebbles in the deformed volcanic matrix with tectonite development along with associated greenschist facies metamorphism, alteration and hydration is remarkable. Flow foliation plane with N-S strike and very low angle （5~ to 10~） easterly dip and N-S axial planar schistosity formed due to later phase isoclinal folding can be clearly identified in the field. Basic intrusives are quite common in the surrounding area. All the observations including the field setting and geochemistry clearly demonstrate ocean-continent subduction as the tectonic environment of the study area.

关键词： kadiri schist belt Tectonics Unconformity contact Ocean-continent subduction Andhra Pradesh Cuddapah basin Greenstone belt

Short Term Wind Speed Prediction Using Multiple kernel Pseudo Inverse Neural Network

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International Journal of Automation and computing 2018年第1期15卷 66-83页

作者： S.P.Mishra P.k.dash Multi-disciplinary Research Centre (MDRC) Department of Electrical EngineeringSiksha "O" Anusandhan University

An accurate short-term wind speed prediction algorithm based on the efficient kernel ridge pseudo inverse neural network （kRPINN） variants is proposed in this paper. The use of nonlinear kernel functions in pseudo inverse neural networks eliminates the trial and error approach of choosing the number of hidden layer neurons and their activation functions. The robustness of the proposed method has been validated in comparison with other models such as pseudo inverse radial basis function （PIRBF） and Legendre tanh activation function based neural network, i.e., PILNNT, whose input weights to the hidden layer weights are optimized using an adaptive firefly algorithm, i.e., FFA. However, since the individual kernel functions based kRPINN may not be able to produce accurate forecasts under chaotically varying wind speed conditions, a linear combination of individual kernel functions is used to build the multi kernel ridge pseudo inverse neural network （Mk-RPINN） for providing improved forecasting accuracy, generalization, and stability of the wind speed prediction model. Several case studies have been presented to validate the accuracy of the short-term wind speed prediction models using the real world wind speed data from a wind farm in the Wyoming State of USA over time horizons varying from 10 minutes to 5 hours.

关键词： Wind speed prediction pseudo inverse neural network kernel ridge regression nonlinear kernels firefly optimizatiotl.

Adaptive neighbor constrained deviation sparse variant fuzzy c-means clustering for brain MRI of AD subject

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Visual Informatics 2021年第4期5卷 67-80页

作者： sukanta Ghosh Amlan Pratim Hazarika Abhijit Chandra Rajani k.Mudi Department of Instrumentation&Electronics Engineering Jadavpur UniversityKolkata700106India

Progression of Alzheimer’s disease(AD)bears close proximity with the tissue loss in the medial temporal lobe(MTL)and enlargement of lateral ventricle(LV).The early stage of AD,mild cognitive impairment(MCI),can be traced by diagnosing brain MRI scans with advanced fuzzy c-means clustering algorithm that helps to take an appropriate *** this paper,firstly the sparsity is initiated in clustering method that too rician noise is also incorporated for brain MR scans of AD ***,a novel neighbor pixel constrained fuzzy c-means clustering algorithm is designed where topoloty-based selection of parsimonious neighbor pixels is *** adaptability in choice of neighbor pixel class outliers more justified object edge boundary which outperforms a dynamic cluster *** proposed adaptive neighbor constrained deviation sparse variant fuzzy c-means clustering(AN_DsFCM)can withhold imposed sparsity and withstands rician noise at imposed sparse *** novel algorithm is applied for MRI of AD subjects and normative data is acquired to analyse clustering *** data processing pipeline of theoretically plausible proposition is elaborated in *** experimental results are compared with state-of-the-art fuzzy clustering methods for test MRI *** evaluation and statistical measures are studied to meet both image processing and clinical neurophysiology *** the performance of proposed AN_DsFCM is significantly better than other methods.

关键词： MRI Fuzzy c-means Neighbor information modeling Sparse Rician noise AD